Closed-circuit relay



P. KARDAETZ.

CLOSED CIRCUIT RELAY.

- 'APPLXCATION FILED DEC. 13. 1921.

1 126,993. Patented Aug. 22, 1922.

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' 9 UNITED STATES PATENT OFFICE.

PAUL KARIDAETZ, OF BERLIN-REINIGKENDORF, GERMANY, ASSIGNOR TO SIEMENS & EALSKE, AKTIENG-ESELLSCHAFT, OF SIEMENSSTADT, NEAR BERLIN, GERMANY, A.

CORPORATION OF GERMANY.

CLOSED-CIRCUIT RELAY.

To all whom it may concern:

Be it known that I, PAUL KARDAETZ, a. citizen of the German Empire, residingat Berlin-Reinicke'ndorf, ermany, have 1nvented certain new ad useful Improvements in Closed-Circuit Relays, for which .I have filed applications for patent in the following countries: Germany, December 11th, 1920, Serial No. 54,994; France, November 1st, 1921, Serial No. 151,366, England, November 1st, 1921, Serial No. 29,010/21; Belgium, November 2nd, 1921, Serial No. 239,567, and of which the following is a specification.

In working with relays operating on a .closed circuit,-wherein the armature is intended to drop into off position when the circuit is once opened, the disadvantage exists that in the case of very short interruptions of the closed circuit current flowing through the winding of the relay, the armature does not drop. This occurs because in the case of'a sudden interruption of the current, the magnetic lines of force issuing from the poles of the relay and passing into the armature, do not dlsappear instantly but only after the exp1ration of a certain period of time, however shortit may be. When therefore, in the case of a sudden interruption of the current, the armature is caused by the actlon of its own weight or of a spring, to move a slight distance away from its poles, it still remains within a magnetic field of considerable strength by which the armature s still attracted to a certain degree. Thus, if a new closure of the circuit should occur before the former field has entirely dlsappeared,'the armature will be attracted anew.

The short interruption of the current results, therefore, only in produclng a temporary detachment of the armature but not in a complete drop of the latter.

Attempts have already been made to remove those disadvantages by mak ng the magnetic pull upon the armature very slight so that only a slight weakening of the magnetic field is required in order to cause the armature to drop.

This arrangement has, however, the .dis-

advantage of rendering the relay very sena tendency to drop into ofi sitive to vibration, that is to say, slight mechanical forces acting upon the relay have the effect of causing the armature to Spee1fication of Letters Patent. Pate t d A 22 1922 Application filed December 13, 1921.

Serial No. 522,116.

drop without the current having been interrupted.

The present invention has for its object to provide an improved closed circuit relay wherein the above disadvanta 'es are obviated, and wherein a certain rop of the armature will take place even in the case of interruptions of the current of extremely short duration.

This object is attained by changing 'the path of the magnetic lines of force entermg or passing through the armature at the very beginning of the dropping movement of, the armature in such manner that, although there still remains a path through the armature available for these lines of force, they will not be able, in taking this path, to exert any longer any pull upon the armature, tending to restore it to its .ori inal on position.

he effect of this arrangement may be further increased by changing the path for the lines of force through the armature initiated by the interruptlon of the current;

to such an extent that a torque or pull on the armature in the opposite direction is generated whereby the armature is completely moved into and maintained in its oil position.

The accompanying drawings illustrate constructional examples of thls invention.

Figures 1 and 2 illustrate in two different working positions spring force alone in its dropped posltion; an

Figures?! to 5 illustrate an arrangement 1n three different working positions, wherean arrangement .wherem the dropping armature is kept by in the springforce is assisted by the re-' I is a contact spring fixed to the armature;

it may serve in the circuits in which the relay is used, for instance to close the contacts 8 or 9 according to the position of the armature.

Figure 1 shows the armature in the on position. When the current flowing through the electromagnet is interrupted, there will be formed, immediately on the commencement of the dropping movement, an air gap between the surfaces 4 and 5 and the magnet poles. The result of this is that owing tothe considerable resistance offered to the fiux by the air gap near the ends of the armature the slowly disappearing magnetic lines of forcewill immediately be crowded together at the portions 10 and 11 of the poles where they will encounter only a'small air gap resistance, and at these points the lines will pass transversely through the armature, close to the axis of the latter, whereas the former magnetic fieldin the air gap between the armature ends and the pole pieces will immediately cease. When the magnetic field is again created by a fresh closure of the circuit, this "magnetic field will naturally be generated first between the pole portions 10 and 11. But since the magnetic field generated in the armature between these pole portions traverses the armature transversely and near or at its pivotal center, 1t cannot cause any return movement, of the armature to on position and therefore the armature will be caused by the action of the spring 11 to completely move into the position shown in Figure 2, even after the relay is completely reenergized.

Figures 3 to 5' illustrate a constructional example wherein the armature 2 has such a shape that when it commences to drop from the position shown in Figure 3, the re-energization of the relay will now assist the spring in moving the armature into the off position.- The manner of operation in this case is again such, that when the relay circuit is opened, a large air gap will immediately form between the armature ends and the pole faces, and the remaining lines of force will be crowded together at those ,points of the poles situated opposite the pivotal center of the armature. These lines of force will therefore pass through the armature at a point at which they are not able to exert any torqueupon it as is shown in Figure 4.

The magnetic field which is regenerated as a consequence of a re-energization of the relay, then serves in combination with the action of the spring 6, to attract the armature in the opposite direction as will be clearly perceived from Figure 5, in which the armature is shown in full flf position. Instead of moving the armature into off position by means of a spring as shown, it

is of course possible to obtain the same effect by a gravity device as an equivalent of the spring action. 7

Since comparatively large surfaces of the armature contact with the pole pieces when the relay is energized, it is almost impossible for the armature to drop off as a result of mechanical vibration notwithstanding the sensitiveness of the relay for short interruptions of current.

For the purpose of attaining a very high degree of sensitiveness of the relay, it is possible to employ pole pieces and armatures of therelay having weak magnetic saturation so that the shifting of all the lines of force in the pole pieces to a predetermined place can be more easily effected.

I claim 1. A closed circuit relay having poles and an armature designed to have an on and oil position and being pivotally disposed midway between its ends and between said poles and permitting the flux to pass lengthwise through it when in on position, means tending to throw said armature into off positionand adapted to partly remove it from the on position when the relay is temporarily de-energized, said armature being wider at its central portion than at its ends, causing the re-energization fiux to pass transversely through said portion when the armature is partly removed from the on position, to permit said throw-01f means to remove it entirely into off position.

2. A closed circuit relay having poles and an armature designed to have an on and off position and being pivotally disposed midway between its ends and between said poles and permitting the flux to pass length wise through it when in on position, means tending to throw said armature into off position and adapted to partly remove it from the on position when the relay is temporarily de-energized, said armature being 'wider at its central portion than at its ends, causing the re-energization flux to pass transversely through said portion when the armature is partly removed from the on position, to permit said throw-off means to remove it entirely into off position, said armature when approaching ofi position permitting the re-encrgization flux to pass lengthwise through it, but in a direction reverse to that when in on position, to assist said throw-oil means to completely move the armature into and hold it in off position.

3. A closed circuit relay having poles and a diamond shaped armature designed to have an on and ofi'.position and being pivotally disposed midway between its ends and between said poles and permitting the flux to pass lengthwise through it when in on position, a spring tending to throw said armature into off position and adapted to partly remove the armature from the to pass transversely through said central portion when the diamond ends are partly removed from the on position to permit said spring to move the armature entirely into the off position. p

4. A closed circuit relay having poles and a diamond shaped armature designed to have an on and off position and being pivotally disposed midway between its ends and between said poles and permitting the flux to pass lengthwise through it when in on" position, a spring tending to throw said armature into ofi position and adapted to partly remove the armature from the on position when the relay is temporarily de-energized, the larger central portion of said armature causing the re- In testimony whereof I aifix my signature. 1

PAUL KARDAETZ. 

